Gracixalus huaping sp. nov.

Figs 6 A, 7, 8

Type material.

Holotype • GXNU YU 000517, an adult male, was collected on 3 May 2022 by Guohua Yu from Huaping National Natural Reserve, Longsheng, Guangxi, China (25°36'44"N, 109°56'19"E, 1474 m elevation).

Paratypes • Two adult males (GXNU YU 000512, GXNU YU 000516) and four adult females (GXNU YU 000511, GXNU YU 000513, GXNU YU 000514, GXNU YU 000515) were collected from the type locality at the same time by Guohua Yu.

Etymology.

The specific epithet is named for Huaping, Guangxi, China, where the species was collected. We suggested “ Huaping small tree frog ” for the common English name and “ 花坪纤树蛙 (Huā Píng Xiān Shù Wā) ” for the common Chinese name.

Diagnosis.

The new species is assigned to genus Gracixalus based upon the following set of morphological characters: the presence of intercalary cartilage between terminal and penultimate phalanges of digits, tips of digits enlarged to discs bearing circum-marginal grooves, vomerine teeth absent, inner (first and second) and outer (third and fourth) fingers not opposable, and an inversed Y-shaped dark brown marking on the dorsum (Fei 1999; Yu et al. 2019; Tran et al. 2023).

The new species can be distinguished from its congeners by a combination of the following morphological characters. (1) SVL 26.6–28.8 mm in males and 29.8–32.8 mm in females; (2) vomerine teeth absent; (3) dorsal surface yellowish brown; (4) few conical tubercles on dorsum; (5) internal vocal sac in males, vocal sac opening oval and rim of the opening dark brown; (6) throat smooth; (7) finger webbing rudimentary; (8) linea masculina present in males; (9) snout rounded; (10) tibiotarsal articulation reaching eye; (11) tibiotarsal projection absent; (12) ventral surface translucent, yellowish-white; (13) belly granular; (14) nuptial pads present on finger I; (15) heels overlapping when legs at right angle to body; (16) iris golden brown; and (17) flank rough with white tubercles.

Description of holotype.

Small size (SVL 28.6 mm; Table 3); head wider (HW 10.9 mm) than long (HL 9.0 mm); snout rounded, slightly projecting beyond margin of lower jaw in ventral view, rounded in profile; canthus rostralis rounded; nostril oval, protuberant, closer to tip of snout than eye; loreal region oblique, slightly concave; interorbital distance (IOD 3.3 mm) equal to internarial distance (IND 3.3 mm) and greater than upper eyelid width (UEW 2.5 mm); eye large, horizontal diameter (ED 3.2 mm) equal to snout length (SL 3.2 mm); pupil oval, horizontal; tympanum distinct (TD 1.5 mm), nearly equal to half of ED; supratympanic fold distinct, extending from posterior corner of eye to above insertion of arm; vomerine teeth absent; tongue notched posteriorly; single internal vocal sac, vocal sac opening oval and rim of the opening dark brown.

Forelimbs relatively strong; forearm and hand length (FHL 14.3 mm) 50 % of SVL; relative finger lengths I <II <IV <III; fingers webbing rudimentary; tips of all fingers expanded into discs with circum-marginal grooves; subarticular tubercles prominent and rounded, formula 1, 1, 2, 2; two metacarpal tubercles, the inner oval and the outer rounded; nuptial pad present at the base of the first finger, prominent.

Heels overlapping when legs at right angle to body; the relative lengths of the toes I <II <III = V <IV; tibiotarsal articulation reaching the middle of the eye when hindlimb adpressed to body; tip of toes expanded into discs with circum-marginal grooves; toe discs slightly smaller than finger discs; toes webbed, webbing formula I 2–1.5 II 1.3 – 2 III 1.2 – 2 IV 2 – 1.3 V; subarticular tubercles prominent, round, formula 1, 1, 2, 3, 2; supernumerary tubercles present; inner metatarsal tubercle oval, outer metatarsal tubercle absent.

Dorsal surface rough, scattered with a few conical tubercles on the upper eyelids, head, dorsum, and limbs; flank and head side rough, scattered with white tubercles; throat relatively smooth; chest, belly, and ventral surface of thighs rough with many white tubercles.

Coloration of holotype.

In life, dorsal surface light yellowish-brown; a dark yellow-brown inverted Y-shaped marking on dorsal surface covering interorbital region, bifurcating into two branches on shoulder and extending posteriorly; dorsal surface of limbs yellow-brown with dark brown stripes; flanks and ventral yellow white; iris golden brown (Fig. 6 A).

In preservative, color faded but pattern same as in life; dorsal surface gray-brown with a dark brown inverted Y-shaped marking; light brown stripes on limbs; ventral surface gray-white (Fig. 7).

Sexual dimorphism.

Males have nuptial pad on the base of finger I and internal single subgular vocal sac. Additionally, males have linea masculina.

Morphological variation.

The inverted Y-shaped marking on the dorsum in paratype GXNU YU 000513 is discontinuous. Paratypes GXNU YU 000512, GXNU YU 000515, and GXNU YU 000516 have much more dark blotches on throat, chest, and belly (Fig. 8).

Distribution and ecology.

The new species is known only from the type locality. Probably the new species is restricted to bamboo forest with evergreen forest (Fig. 9 a). All specimens were collected in daylight and were found in open-ended bamboos filled with a little water. Eggs with gel nests were deposited on the walls of open-ended bamboos (Fig. 9 b), implying that the new species has entered breeding season in April. In daylight no calls were heard.

Comparisons.

Gracixalus huaping sp. nov. differs from its sister taxon G. jinxiuensis by having smaller maximum body size in males (SVL up to 28.8 mm vs. up to 34.3 mm), vocal sac opening oval and rim of the opening dark brown (vs. vocal sac opening slitted and edge of the opening immaculate; Fig. 10), skin of venter more granular (Fig. 10), linea masculina present (vs. absent; Fig. 6), longer foot, and heels overlapped (vs. just meeting) (Table 5).

The new species differs from G. ananjevae by having smaller body size (SVL 26.6–28.8 mm in males and 29.8‒32.8 mm in females vs. male 32 mm and female 43 mm), finger webbing rudimentary (vs. finger webbing formula I 2‒2 II 2 ‒ basalIII 3 ‒ 2.75 IV), and presence of white granules around anus and on limbs (vs. absent); from G. carinensis by having smaller body size (SVL 26.6–28.8 mm in males and 29.8‒32.8 mm in females vs. 30.2–38.1 mm in males and 40.3‒41.8 mm in females), less developed toe webbing, and conical tubercles on dorsum present (vs. absent); from G. gracilipes by having bigger body size in males (SVL 26.6–28.8 mm vs. 20–24 mm), snout rounded (vs. triangularly pointed), dorsal surface light yellowish-brown (vs. greenish), and nuptial pads present just on finger I (vs. nuptial pads present on fingers I and II); and from G. guangdongensis by skin of throat smooth (vs. granular), white patch on temporal region absent (vs. present), dorsal surface light yellowish-brown (vs. brown), ventral surface translucent and yellowish-white, throat smooth, chest and belly granular (vs. throat and chest creamy white, belly light brown, semi-transparent), and iris golden-brown (vs. brown).

Gracixalus huaping sp. nov. differs from G. jinggangensis Zeng, Zhao, Chen, Chen, Zhang & Wang, 2017 by nuptial pads present just on finger I (vs. nuptial pads present on fingers I and II) and heels overlapped (vs. just meeting); from G. lumarius by having smaller body size (SVL 26.6–28.8 mm in males and 29.8–32.8 mm in females vs. 38.9–41.6 mm in males and 36.3 mm in a female), dorsal surface rough scattered with tubercles (vs. dorsal surface of head and back covered in dense and distinctive white conical tubercles), dorsum light yellowish-brown (vs. yellow), and supratympanic fold distinct (vs. indistinct); and from G. medogensis by dorsal surface and flank rough scattered with tubercles (vs. relatively smooth), dark brown mark beginning between eyes bifurcated into two wide branches after the back of shoulders (vs. bifurcated into two relatively narrow branches before the back of shoulders), dorsal color light yellowish-brown (vs. grass green), finger webbing rudimentary (vs. absent), and ventral surface yellowish-white (vs. pale green).

Gracixalus huaping sp. nov. differs from G. nonggangensis by having smaller body size (SVL 26.6–28.8 mm in males and 29.8‒32.8 mm in females vs. 29.9–35.3 mm in males and 33.6‒38.0 mm in females), dorsal surface light yellowish-brown with dark-brown mark (vs. yellowish-olive with dark-green mark), finger webbing rudimentary (vs. absent), linea masculina present (vs. absent), nuptial pads on finger I (vs. absent), and iris golden-brown (vs. olive); from G. quangi by having larger body size (SVL 26.6–28.8 mm in males and 29.8–32.8 mm in females vs. 21.4‒24.5 mm in males and 26.6‒27.3 mm in females), dorsal surface light yellowish-brown (vs. olive-green), vocal sac internal (vs. external), finger webbing rudimentary (vs. absent), snout rounded (vs. triangularly pointed), brown under the supratympanic fold (vs. pale turquoise), tibiotarsal projection absent (vs. present), ventral surface translucent and yellowish-white with dark blotches (vs. opaque white with translucent pale-green margins), and iris golden-brown (vs. bronze); and from G. quyeti by dorsal color light yellowish-brown (vs. brownish to moss-green), head wider than long (vs. head longer than wide), tibiotarsal articulation reaching eye (vs. reaching to snout), supratympanic fold distinct (vs. indistinct), throat white, clouded with dark in preservative (vs. yellow-white with brown marbling), and forelimb, dorsal parts of thighs, tibia, and foot brown with dark brown bands (vs. moss-green with dark brown bands).

The new species differs from G. sapaensis Matsui, Ohler, Eto & Nguyen, 2017 by having tubercles on dorsum (vs. dorsum smooth), white warts on edge of upper jaw, temporal region, flanks and limbs (vs. absent), throat, chest, belly and ventral surface of forelimbs white with dark specks (vs. light yellow), and dorsal surface light yellowish-brown (vs. golden ochre); from G. seesom by having bigger body size (SVL 26.6–28.8 mm in males and 29.8–32.8 mm in females vs. 21.6–23.0 mm in males and 23.2‒25.4 mm in females), snout rounded (vs. triangularly pointed), dorsal surface rough scattered with tubercles (vs. smooth), dorsal surface light yellowish-brown with dark brown inverted Y-shaped marking (vs. tan), and nuptial pads on finger I (vs. absent); from G. supercornutus by having bigger body size (SVL 26.6–28.8 mm in males vs. 22.0– 24.1 mm), dorsal surface light yellowish-brown (vs. dorsum green with brown spots), snout rounded (vs. pointed), white patch on temporal region absent (vs. present), tubercles on dorsal surface small (vs. considerable bigger horn-like projections in supraorbital area, around cloaca, and on dorsum, forelimbs and hindlimbs), and tibiotarsal projection absent (vs. present); and from G. tianlinensis by having smaller body size (SVL 26.6–28.8 mm in males and 29.8–32.8 mm in females vs. 30.3–35.9 mm in males and 35.6‒38.7 mm in females), vocal sac internal (vs. external), finger webbing rudimentary (vs. absent), and nuptial pads only on finger I (vs. on fingers I and II), and iris golden-brown (vs. bronze).

Gracixalus huaping sp. nov. differs from G. trieng Rowley, Le, Hoang, Cao & Dau, 2020 by having smaller body size in males (SVL 26.6–28.8 mm vs. 37.2–41.4 mm), throat and chest white with dark specks (vs. throat and chest yellow or yellowish brown with pinkish mottling), linea masculina present (vs. absent), and nuptial pads only on finger I (vs. on fingers I and II); from G. yunnanensis by vocal sac internal (vs. external), and flank rough with tubercles (vs. smooth); from G. ziegleri Le, Do, Tran, Nguyen, Orlov, Ninh & Nguyen, 2021 by skin of throat smooth (vs. granular), linea masculina present (vs. absent), and tibiotarsal articulation reaching eye (vs. reaching tip of snout); and from G. truongi Tran, Pham, Le, Nguyen, Ziegler & Pham, 2023 by having smaller body size (SVL 26.6–28.8 mm in males and 29.8–32.8 mm in females vs. 32.2–33.1 mm in males and 37.6–39.3 mm in females), dorsal surface light yellowish-brown (vs. moss green with grey), dorsal surface rough scattered with sparse tubercles (vs. smooth), and linea masculina present (vs. absent).